I've got a cheaper set on my car. The ride is certainly stiff, and as above it does hop a little over bumps. If you drive long distance down motorways, expect to be literally bobbing out of your seat on bumps. The whole comfort is comprised in general when you lower it, especially if its down 70mm or so. I was going to get a second hand set of KW Var 2's from German eBay, but I just lost out on the auction at £270 IIRC - a real bargain!
But, I like it, I don't mind the bumpiness, the car looks cool as hell slammed, and its increased the handling 10 fold.